Organ intensity control



Patented Oct. 23, 1951 ORGAN INTENSITY CONTROL Francis M. Schmidt, North 'Tonawanda, N. Y., as-

signor to The Rudolph Wurlitzer Company, North Tonawanda, N. Y., a corporation of Ohio Application January 8, 1948, Serial No. 1,112

Claims. 1

This invention relates to controls for electrical musical instruments and concerns particularly intensity controls for electronic organs.

In the operation of electrical musical instruments, and particularly electronic organs of the type to which the present invention relates, there is provided a plurality of sets or banks of tone generators which are selectively operable to generate tones in the form of electrical waves or pulsations, which waves are combined, amplified and transmitted to a loudspeaker or other sound reproducing apparatus, wherein they are transformed and emitted as sound. In such instruments, it is desirable that in addition to the general volume or level control for the entire instrument, means be provided for adjusting the volume or level of the individual sets of tone generators in respect to each other, whereby the desired musical effects at the sound outlet may be obtained.

It is an object of the present invention to provide an improved control circuit for an electrical musical instrument, and more specifically to provide an improved intensity control arrangement and circuit for an electronic organ of the type defined, so as to provide a simplified arrangement of parts and improved operating characteristics.

More specifically stated, among the objects of the invention are to provide an improved intensity control arrangement having a reduced number of parts, greater flexibility of adjustment and minimized disturbance of the desired sound level, either upon operation or in the event of failure of one or more of the switch contacts provided in the system.

Various other objects, advantages and features of the invention will be apparent from the following specification, when taken in connection with the accompanying drawings, where a preferred embodiment is set forth for purposes of illustration.

In the drawings wherein like reference'numerals refer to like parts throughout, Fig. 1 is a diagrammatic view of an electric musical instrument and specifically an electronic organ incorporating an intensity control circuit constructed in accordance with and embodying the principles of the invention; Fig. 2 is a detailed view showing a part of the tone generators, and Fig. 3 is an electric circuit diagram illustrating the control arrangement of the invention.

The particular electronic organ illustrated in Fig. 1 comprises a casing or housing It arranged to support a swell manual or keyboard I2, a great manual it and a pedal clavier l6.

There is also provided a volume control pedal l8, by means of which the over all volume or level of the instrument may be controlled, and a series of stop tablets 28 by means of which the various tone generators are caused to be activated and the volume thereof controlled in the particular instrument shown.

Disposed within the casing I8 is a plurality of banks of tone generators 22 which may, for example, be of the type and kind shown in the patent to Hoschke No. 2,015,014 issued September 17, 1935. More specifically, and as shown in Fig. 2, these tone generators comprise a series of vibratory reeds 2 individually disposed within cells 26, each reed having associated therewith an adjustable pick-up screw 28 forming with its associated reed a capacitor variable in accordance with the reed vibrations. The several banks of tone generators are physically constituted to provide tones or signals of different quality such as flute, viole, etc. The circuit connections to the reeds and pick-up screws in respect to the intensity control will be later described.

Air is admitted into the cells 26, so as to cause the selective vibration of the reeds by means of a series of pallet valves 39, the selective operation of which is controlled by the keys of the manuals or of the pedal clavier in accordance with the selection of the stops 26!. This control is effected by coupler boards, as shown at 32 and 34, the coupler boards containing switches selectively actuated by the keys of the manuals and pedal clavier and by the selected stops, so as to cause the operationof the desired pallet valves to thereby admit actuating air to the desired reeds. The air supply for the reeds is provided from a blower 35.

The electric signal output from the tone generators is transmitted to an amplifier structure 38-43 arranged to actuate a speaker, as indicated at 42, Fig. 3. The volume control pedal l8 has associated therewith a control mechanism 44 adapted to control the degree of amplification effected by the amplifier 36 to thereby control the volume or level of the entire instrument, as previously described.

Certain of the stops 2% effect the selection of the tone generators for operation, as previously described, whereas other of the stops are provided for intensity control purposes to selectively control the intensity or level of the individual banks or sets of tone generators. These intensity control stops are illustrated in Fig. 3. Referring to Fig. 3, and in accordance with the present invention, there is provided a full wave rectifier 50 powered from a suitable source of A. C. supply, as indicated at 52. The positive output D. C line from the rectifier is indicated at 54 and is connected to ground through a stabilizing resistor 56. A filter comprising a choke 58 and a condenser 66 is arranged in the line 54 to minimize pulsations.

As illustrated in Fig. 3, the stop tablets 62 and 64 are provided for coaction with the pedal clavier and are respectively the loud and soft stops for the pedal reeds 66. The stop tablets '68 and I6 are arranged for association with the swell manual or keyboard and are respectively the loud and soft stop controls for the flute bank of reeds I2. The stop tablets I4 and I6 are also associated with the swell manual and are respectively the loud and soft controls for the viole reeds 78. The stop tablets 80, 82, 84 and 86 are associated with the great manual and controlwise are duplicates respectively of the stop tablets 68, 70, I4 and '56. In the embodiment shown, no stop tablet intensity control is presented for the diapason reed bank 88 and the celeste reed bank 96.

Referring further to Fig. 3, it will be seen that the full voltage D. C. line 54 is connected by means of three equal isolating resistors 92 to Wires 94, 96 and 68 leading to the stop tablets. The full voltage line 54 is also connected by means of a wire I60 to a voltage divider generally indicated by the numeral I02, and comprising a series of resistors I64, I86, I06 H6, H2, H4, H6, IE8, I28 and I22 connected to ground.

A line I24 leads from line I09 through a resister I26 to line I28 connected to the diapason reeds, so that current is supplied continuously thereto at a value determined by the resistor I26. Similarly, line I24 connects by means of a resistor I36 to line I32 leading to the celeste reeds, whereby these reeds also have a continuous voltage applied thereto at a value determined by the resistor I38. A filter structure comprising the condensers I36 and I36 is disposed between the lines I28 and I82. The ground connection from the diapason reeds is through a resistor I38, whereas the ground connection for the celeste reeds is through a resistor, as shown at I40. The ground return to the rectifier comprises line I42 and associate resistor I44, as will be understood. The capacitors I46 and I48, which are disposed in parallel respectively with resistors I38 and I46, comprise a part of the signal circuit from the tone screw-vibratory reed capacitors to the ampliflers as is more fully set forth in said Hoschke Patent No. 2,015,014. As shown in Fig. 2, wherein a portion of the celeste reed bank is illustrated, it will be seen that the reeds and the tone screws are respectively connected in parallel groups to the voltage supply wire I32 and the wire I50 leading to the amplifier, as shown.

It will be seen that by reason of the connections described, continuous and constant voltage of predetermined value is applied respectively to the diapason and celeste reeds whereby to determine the volume of the tone output therefrom upon reed actuation.

As to the pedal, flute and viole reeds, means is provided for varying the voltage applied thereto whereby to vary the tonal volume, as previously indicated. Referring to Fig. 3, it will be seen that the voltage divider includes a tap switch I52 by means of which any one of several different voltages, as determined by the dropping resistors.

pacitors I60 to a line I62 connecting with the pedal reeds. Similarly, the voltage divider includes a tap switch I64 by means of which any one of several different voltages may be tapped off and supplied to a line I66 leading through a resistor I68 and a filter comprising the resistors Ill] and the capacitors I'I2 to a line I14 leading to the viole reeds. Still further, the voltage divider includes a tap switch M6 by means of which one of several voltages may be tapped off and applied by means of a line I'IB through a resistor I60 and a filter comprising a resistor I82 and capacitors I84 to a line I86 leading and connected to the flute reeds. The ground return for the flute, pedal and viole reeds comprises resistors I88, I96 and I62 respectively, as shown.

It will be seen that by reason of the tap switch connections thus provided, a predetermined voltage, determined by the setting of the adjustable switches, will, at all times, be applied through the tap switches to the respective banks of reeds.

Referring further to Fig. 3, it will be seen that the wire 96 interconnects with a normally closed switch I94, adapted to be opened upon depression of the soft stop tablet 6 4, and a normally open switch I96 adapted to be closed on the depression of the loud stop tablet 62. Normally, the full voltage of line 96, which is higher than that applied through the tap switches previously described, is interconnected with line I98 through the normally closed switch I94. This condition exists when both stop tablets are unactuated or undepressed. It also exists when the loud stop tablet 62 is depressed, as such depression merely closes the switch I96 whereby to form a further parallel circuit connecting wire 96 to wire I98.

So long as the loud stoptablet remains down, depression of the soft stop tablet will not disturb the high voltage applied to the reeds, due to the fact that switch I96 is closed; but when the loud stop 62 is up and the soft stop 64 is down, both switches I96 and I94 will-be open, and the predetermined lower voltage applied will be that impressed through the tap switch I52, adjustably determined by the setting thereof.

It will be seen that each stop tablet is provided with but a single set of contacts. It will furthermore be noted that should one or both sets of contacts I94 and I96 fail, by reason of accumulated dirt or other. cause, the only effect will be to maintain the reeds at the lower applied voltage, due to the insured connection thereto through the tap switch structure. At no time is a zero potential applied to the reeds, regardless of the position of the complementary stop tablets. By this means the. applied voltage fluctuation never exceeds the difference between the loud and soft intensities, which minimizes shock and unwanted noises in the system. The filters I58 and I60 cooperate in this regard, providing a minimum shock in the voltage applied to the reeds, as the intensity stops are operated.

Referring to the swell and great manual controls for the flute and viole reeds, it will be seen that the swell manual soft stop III for the flute reeds cooperates with a normally closed switch 200, whereas the loud stop 68 coacts with and is arranged to close a normally open switch 202. Similarly the soft flute stop 82 of the great manual cooperates with the normally closed switch 204, whereas the loud viole stop on the great manual cooperates with and is arranged to actuate a normally open switch 206.

Normally when all stops are undepressed both switches 200 and 204 will be closed'whereby to apply the full voltage of wire 94 through a series circuit comprising the switch 200, wire 208, switch 204 and wire 2 I 0 leading to the flute reeds. A loud intensity results. This condition continues upon depression of either the loud stop 68 or the loud stop 80, or both, the closing of switches 202 and 206 merely providing additional connection between the supply wire 94 and the wire ZIIl. However, the depression or operation of either of the soft stops III or 82 will break the series circuit, so that the lower voltage intensity applied through tap switch I16 results, unless one or the other of the loud stops 68 or 80 remains actuated in which event such loud stop willremain in control.

It will thus be seen that when no stops are depressed, a loud intensity results, but when a soft stop for either manual is actuated a low intensity is effected, unless the loud stop for one or the other of the manuals has been actuated. As in the case of the pedal stops, these results are accomplished by means of single switches associated with the stop tablets. The lower intensity is adjustable by means of the tap switch I16, and at no time is a greater voltage fluctuation than the difference between loud and soft intensity applied to the reeds. The filter comprising the resistor I82 and the capacitors I84 cooperates to minimize voltage shock in the reeds upon operation of the stops.

As to the viole reeds a similar switching arrangement is provided comprising a normally closed switch 2I2 operated by the soft stop I6 of the swell manual; a normally open switch 2I4 operated by the associated loud stop I4; a normally closed switch 2I6 associated with the soft stop 86 of the great manual; and a normally open switch 2I8 arranged for actuation by the associated loud stop 84; these switches being arranged to interconnect supply wire 98 with wire 220 connecting with the viole reeds. The operation of these switch contacts is believed to be clear from what has heretofore been pointed out in connection with the flute reed switch structures.

The reed banks are diagrammatically illustrated herein, but preferably are interconnected as shown more in detail in my companion application, Serial No. 1,113, filed of even date herewith. The amplifier structures 38 and 40, arranged to amplify and emit as sound through the speaker 42, the signals or voltage variations provided by vibration of the reeds, are preferably as shown in my U. S. Patent No. 2,555,295 granted on May 29, 1951, and U. S. Patent N0. 2,559,802 granted on July 10, 1951.

The present invention provides a simplified switching arrangement for intensity control, minimizing the required number of parts and minimizing failures in operation. Moreover, should such failure occur, at least the lower intensity of sound from the reeds will nevertheless be insured. The arrangements and circuits provide ready adjustability of the lower intensity polarizing voltages, and minimum voltage shock upon the reeds at all times.

While the invention has been herein disclosed as applied to the control of a particular electronic organ, and specifically to the intensity or volume control of the tone generators thereof, it is obvious that various changes may be made in the specific embodiment set forth without departing from the spirit of the invention. Accordingly the invention is not to be limited to the specific structures shown and described, but? only as indicated in the following claims.

The invention is hereby claimed as follows:

1. An electronic musical instrument comprising a sound producing system having a plurality of tone generators, a tone outlet, and means for selectively controlling the tonal volume of saidgenerators comprising means continuously interconnected with said system to effect the operation thereof at one predetermined volume, meansadapted for interconnection with said system to effect the operation thereof at a predetermined"- different volume, a pair of manual control mem bers, and a pair of complemental control switches connected respectively with said manual control. members for controlling the selective connectionv of said latter means to the system for effective operation.

2. An electronic musical instrument comprising: a sound producing system having a plurality of. tone generators, a tone outlet, and means for selectively controlling the tonal volume of said. generators comprising means continuously inter-- connected with said system to effect the operation thereof at one predetermined volume, means:

adapted for interconnection with said system to effect the operation thereof at a predetermined. different volume, a manual control switch for selectively connecting said latter means to the: system for effective operation, and mechanism for adjusting the controlling function exerted by at least one of said means.

3. An electronic musical instrument comprising a sound producing system having a plurality of tone generators, a tone outlet, and means for selectively controlling the tonal volume of said generators comprising means continuously interconnected with said system to effect the operation thereof at a predetermined volume, mechanism for adjusting the control exerted by said means, means adapted for interconnection with said system to effect the operation thereof at a predetermined greater volume, and a pair of complemental manual control switches for selectively controlling the connection of said latter means to the system for effective operation.

4. An electronic musical instrument comprising a sound producing system having a plurality of tone generators, a tone outlet, means continuously interconnected with said system for effecting the operation thereof at a predetermined minimum volume, volume increasing means, and means for controlling the action of said increasing means comprising a pair of complemental manual control members, a normally open switch contact arranged for operation by one of said members, a normally closed switch contact arranged for operation by the other of said members, and a switch circuit interconnecting said switches and said volume increasing means whereby the conjoint positioning of said switches determines the effective action thereof.

5. An electronic musical instrument comprising a sound producing system having a plurality of tone generators, a tone outlet, and a plurality of keyboards for controlling the action of said generators, and means for selectively controlling the tonal volume of said generators comprising a pair of complemental manual control members for one of said keyboards, a pair of complemental manual control members for another of said keyboards, a series of switches connected for operation by said members, and volume control means, certain of said switches associated with the control members of different keyboards being con- 'ne'cted series to said volume control means to control the action thereof.

6;. An electronic musical instrument comprising a. sound producing system having a plurality of tone generators, a tone outlet, and a plurality of keyboards for controlling the action of said generators, and means for selectively controlling the tonal volume of said generators comprising a pair of complemental manual control members for one of said keyboards, a pair of complemental manual control members for another of said keyboards, a single switch contact for operationby each of said members, certain of said switch contacts associated with the control members of different keyboards being in series, volume control means, and circuit interconnections between the volume control means and. said switches whereby the position of the switches controls the action of said means.

7.. An. electronic musical instrument comprising a sound producing system having. a plurality of tone generators, a tone outlet, and a plurality of keyboards for .controlling the action of said generators, an electrical potential continuously interconnected with said system to effect theoperation thereof at one predetermined volume, and means for varying the tonal volume of said system comprising volume control means for varying said electrical potential, a manual control switch associated with one of said keyboards, a manual control switch associated with another of said keyboards, and circuit interconnections between both of. said switches and said volume control means for changing the level thereof between the same limits.

8. An electronic musical instrument comprising a sound producing system having a plurality of tone generators, a tone outlet, and means for selectively controlling the tonal volume of said generators comprising an electrical potential applying means continuously interconnected with said system to effect theoperation thereof atone predetermined volume, a voltagedivider for-controlling the level of said potential applying means, a second electrical. potential applying means adapted for interconnection withsaid system to effect the operation thereofat a predetermined diiferent volume, and a manual control switch for selectively connecting said second potential applying means for effective operation.

9. An electronic musical instrument as defined in claim 1, wherein said tone generators comprise a plurality of vibratile reeds, and wherein said means interconnected with the systemto effect the operation thereof comprises polarizing potential applying means for the-generators.

10. An electronic musical instrument as defined in claim 2, wherein said tone genera-tors comprise a plurality of vibratile reeds, and wherein said means interconnected with the systemto effect the operation thereof comprises polarizing potential applying means for the generators;

11. An electronic musical instrument as defined in claim 4, wherein said tone generators comprise a plurality of vibratile reeds, and wherein said means interconnected with the system to effect the operation thereof comprises polarizing potential applying means-for the generators.

12. An electronic musical instrument'cornprising a sound producing system having a plurality of tone generators, a pluralityof' keyboards for controlling the tone generators, .a tone outlet, and means for selectively controllingv the tone volume of said generators comprisingmeanscontinuously, interconnected with saidsystem. .to

eire'ct the operation thereof at one predetermined volume, means adapted for interconnection with said system to effect the operation thereof at a predetermined different volume, .a plurality of manual control switches connected respectively with said keyboards for selectively connecting said latter means to the system for effective operation, and mechanism for adjusting the controlling function exerted by at least one of said means.

13. An electronic musical instrument comprising a sound producing system having a plurality of tone generators, a plurality of keyboards for controlling the tone generators, a tone outlet, means continuously interconnected with .said system for effecting the operation thereof at a predetermined minimum volume, volume increasing means and means for controlling the action of said increasing means comprising a pair of complementalmanual control members for each keyboard, a normally open switch contact connected for operation by one control member for each keyboard, a normally closed switch contact connected for operation by the other control member for each keyboard, and a switch circuit interconnecting said switches and said volume increasing means whereby the conjoint positioning of saidswitches determines the effective :actionthereof.

14. An electronic musical instrument comprising a sound producing system having a plurality of tone generators, a plurality of keyboards for controlling the generators, a tone outlet, and means for selectively controlling the tonal volume of said generators comprising an electrical potential applying means continuously interconnected with said system to effect the operation thereof at one predetermined volume, a voltage divider for controlling the level of said potential applying means, a secondelectrical potential applying means adapted for interconnection with said system to effect the operation thereof at a predetermined different volume, and aplurality of manual control switches connected with said keyboards for selectively connecting said second potential applying means for effective operation.

15. An electronic musical instrument comprising a sound producing system having a plurality of. tone generators, atone outlet, means continuously interconnected with said system for effecting the operation thereof at a predeter' mined volume, volume varying means, and means for controlling the action of said varying means comprising. a pair of complemental manual control members, a normally open switch contact arranged for operation by one of said' members, a normally closed switch contact arranged for operation by theio'ther of said members, and a switch circuit interconnecting said switches. and said volume varying means whereby the conjoint positioningof said switches determines the effective actionthereof.-

FRANCIS'M. SCHMIDT.

REFERENCES CITED The following references are of record'in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,071,649 Miessner et al Feb. 23,1937 2,171,645 Broos Sept. 5, 1939 2,225,196 Miessner Dec. 1'7, 1940 2,237,105: Miessner -11-"; Apr. 1, 1941 

